This invention relates to specialty eyewear, and more particularly to eyewear capable of converting a user's direct line of vision into an angularly offset effective line of vision. We refer to this structure as an eyewear field-of-view changer.
There are many instances in which one might find it convenient to have eyewear capable of the kind of conversion referred to just above. For example, a person who enjoys watching television while lying in bed might appreciate the capability of lying down, in effect staring straight up as if toward the ceiling, and nevertheless comfortably viewing the image on the usual vertically disposed, horizontally displaced television screen. People likewise reclining on a beach might wish to be able to view surrounding scenery without sitting up. As another illustration, readers might enjoy the opportunity to read with a book placed below in the lap while apparently staring generally straight forward without having to bend the neck. Yet another application relates to computer use where one might wish to have a keyboard located adjacent the lap, with a monitor screen displaced laterally as in the case of television viewing mentioned above. Here, a user, while staring generally straight ahead could effectively be selectively viewing the keyboard, and, by lifting the line of vision slightly, selectively directly viewing the monitor screen.
Apparatus for converting one's line of vision generally has been proposed in the past, and a good illustration of prior art apparatus is found in U.S. Pat. No. 2,123,682 issued to Wingate. This patent discloses eyewear which includes a pair of laterally displaced triangular prisms each of which effects a change in apparent line of vision through the mechanisms of twin reflection and twin refraction. A Wingate type appliance, however, has a number of serious limitations. To begin with, the prismatic action which involves twin reflection and twin refraction offers some complications in what should otherwise be simple calculations to achieve a desired selected angular offset. In addition, prismatic structure is relatively cumbersome and heavy, as well as relatively expensive. Further, in an appliance such as that shown by Wingate, assuring proper bilateral alignment of two offset prisms is difficult to achieve, and hard to maintain under circumstances of transverse torsion being exerted upon the optical frame. Yet another drawback of prismatic construction is that it does not readily lend itself to offering a user an option of changing selectively the desired angular offset between the effective line of vision and the actual direct line of vision. Nor does it allow one to "rotate" the effective offset angle.
Proposed according to the present invention is a unique eyewear device which meets all of the convenience objectives set forth above while at the same time avoiding the drawbacks found in a prior art device like that proposed by Wingate.
According to a preferred embodiment of the invention, the proposed eyewear takes the form of a lightweight optical frame that carries of a pair of highly reflective planar optical surfaces which co-act to redirect, accurately and exactly the same for both eyes, a user's direct line of vision to a selected angularly offset effective line of vision. These reflective surfaces are also referred to herein as non-refractive, non-image-reversing, view-line-axis converting reflection means. The mechanism proposed herein, in a pair of disclosed modification, further includes adjustment mechanism which permits a user selectively to change the effective angular offset just mentioned, and/or, the angular "direction" of the offset angle (i.e., rotation).
These and other objects and advantages which are offered by the invention will become more fully apparent as the description that now follows is read in conjunction with the accompanying drawings.